Surgical instruments which have a plurality of functions are known in the art. In combined instruments of this type, there is no need for a changeover between the “individual instruments” needed at any particular time. For example, laparoscopic operations in which a change of instruments usually involves a complex removal from, and introduction into, the trocar, can thus be carried out more efficiently. Combined instruments, for example, for sealing vessels and for cutting tissue are known.
A common use of such instruments is the excision of tissue. During excision, in a first step, tissue is grasped and coagulated. In a second step, the coagulated section is parted with a cutting instrument. The coagulation is carried out to close blood vessels and prevent bleeding during cutting. These steps are repeated as often as needed until the tissue bundle is removed from the body. Procedures of this type are standard for cancerous conditions, for example, in the case of a hysterectomy, wherein the uterus is removed.
An instrument of this type requires a first functional unit for grasping the tissue and a second functional unit for cutting the tissue, wherein a mechanism for transmitting force or movement must be provided. The relevant force can be applied by the user by means of operating elements, for example, a hand trigger or a finger trigger, on a handle.
Surgical instruments belonging to the prior art conventionally have a plurality of actuating elements, wherein each actuating element is assigned to a functional unit. In this way, functional units can be operated separately. For example, a hand trigger for grasping, a finger trigger for cutting, and a separate coagulation switch can be provided. Separate construction of the actuating elements is perceived to be disadvantageous, causing repeated interruptions in the operation because, for example, smooth grasping and cutting in one movement is not possible. The user is also restricted, for example, if the index finger is used for cutting and is no longer available for activating the coagulation process. The various actuating elements also lead to increased costs and comparatively bulky instruments. As a result, it becomes increasingly difficult to maintain oversight of such an instrument during use.
Surgical instruments in which two different functions, specifically grasping and cutting tissue, can be controlled with just one actuating element are also known in the prior art. For example, U.S. Pat. No. 7,628,791 describes an electrosurgical instrument for coagulating and cutting tissue. Three different functions, specifically grasping, coagulating, and cutting the tissue, are controlled with just one actuating element. If the hand trigger provided is moved through a first travel segment, the jaw part closes and, if said trigger is moved farther, a coagulation switch is actuated. If said trigger is moved yet farther, a blade is guided through the clamped tissue. A force must be exerted by the user over the whole range of movement in order to hold the tissue firmly, wherein the counterforce of a spring is overcome. For arresting a grasping position, locking devices are proposed in U.S. Pat. No. 7,628,791, although said locking devices permit only locking before the cutting process takes place. During the cutting process, corresponding locking is not possible and would also be disadvantageous because, in the known device, the cutting knife could not be moved back again. Therefore, the user is restricted when using the instrument described in U.S. Pat. No. 7,628,791 because, for example, during cutting of the tissue, it must be ensured that the tissue is sufficiently well-grasped.